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|
package core
import (
"encoding/binary"
"fmt"
"io"
"strings"
"time"
)
type Marshaler interface {
Marshal() []any
}
type DataType uint8
const (
TypeUnknown DataType = 0x00
TypeHandshake = 0x01
TypePing = 0x02
TypePong = 0x03
TypeTest = 0xFF
)
func ReadDataType(r io.Reader) (DataType, error) {
var data uint8
if err := read(r, &data); err != nil {
return TypeUnknown, err
}
dType := DataType(data)
return dType, nil
}
type Handshake struct {
Version uint8
}
func (t Handshake) Marshal() []any {
return []any{t.Version}
}
func ReadHandshake(r io.Reader) (Handshake, error) {
var t Handshake
err := read(r, &t.Version)
return t, err
}
type Test struct {
Message string
}
func (t Test) Marshal() []any {
return []any{append([]byte(t.Message), 0x0)}
}
func ReadTest(r io.Reader) (Test, error) {
var t Test
err := readString(r, &t.Message)
return t, err
}
type Ping struct{}
func (t Ping) Marshal() []any {
return []any{}
}
type Pong struct {
Timestamp time.Time
}
func (t Pong) Marshal() []any {
return []any{uint64(t.Timestamp.Unix())}
}
func ReadPong(r io.Reader) (Pong, error) {
var (
t Pong
timestamp uint64
)
err := read(r, ×tamp)
t.Timestamp = time.Unix(int64(timestamp), 0)
return t, err
}
//
func readString(r io.Reader, ptr *string) error {
var (
sb strings.Builder
buf byte
)
for {
if err := read(r, &buf); err != nil {
return err
}
if buf == 0x0 {
break
}
if err := sb.WriteByte(buf); err != nil {
fmt.Errorf("cannot write byte to string buffer: %v", err)
}
}
*ptr = sb.String()
return nil
}
func read(r io.Reader, ptr any) error {
err := binary.Read(r, binary.BigEndian, ptr)
if err != nil {
return fmt.Errorf("cannot read: %v", err)
}
return nil
}
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